The present invention relates generally to an absorption heat pump and particularly to a purger therefor.
As industry is booming and the living standard is upgraded, the air-conditioning system is getting more and more popular, which means that more and more electric power is needed. Consequently, developed industrial countries have to find every possible means to develop new kinds of air-conditioning systems which are capable of saving electric power. It is found that absorption heat pump systems driven by heat energy call for the least electrical power. Besides, it is possible to drive the absorption heat pump by recovering heat energy for industrial exhaust fluid so as to utilize energy in very economic way. It was reported that, within the year of 1988, the Japanese sold totally 6541 sets of absorption heat pump, amoung which 2409 sets are over 50 RT.
The absorption heat pump capable of generating either hot or cold water for use and having a working principle different from that of a coventional compression air-conditioning system mainly includes a condenser and an evaporator as in a conventional cooling system, and an absorber and a generator instead of a conventional compressor for respectively absorbing refrigerant by means of absorbing agent and releasing vapor refrigerant produced. The cold-making effect is performed by the evaporator in which the refrigerant is changed from liquid state into gas state. In the circumstances that the absorbing agent is lithum bromide solution and the refrigerant is water, the vapor refrigerant coming from the evaporator is absorbed by the lithum bromide solution in the absorber under an extremely low pressure of about 4-6 mm Hg. Due to the slight leakage of the heat pump and also the oxidation of the heat pump which will produce hydrogen, some non-condensable gas which is neither soluble in the working fluid nor condensable at a lower temperature. With the accumulation of non-condensable gases, the presssure in the absorber will gradually increase, raising the evaporating temperature of the refrigerant. In addition, the non-condensable gas will mix with the vapor refrigerant to form therearound a film hindering the vapor refrigerant from being absorbed by the absorbing agent so that the cooling capacity of the heat pump system is greatly reduced.
Generally, a commercialized absorption heat pump system is provided with a purging device for purging or extracting the non-condensable gas, which is normally achieved by utilizing a nozzle through which the less dense working fluid having absorbed to refrigerant (water) is caused to flow to produce a local low pressure area trapping thereto the non-condensible gas being then discharged to a storage tank. Since the lithum bromide solution has a better absorptivity at a lower temperature, if the temperature of the solution flowing through the nozzle is lowered to increase the ability of the lithum bromide solution in absorbing the vapor refrigerant, the purging effect will be improved or a lower pressure area will be obtained. This is the reason why some manufacturers add in the heat pump system a cooling pipeline. However, this can be troublesome if there is blockage therein; and leakage may occur and change the density of the working fluid or the operating situation of the system if there is a corroded pipe in the pipeline.